1. Technical Field
The present invention generally relates to an in-memory virtual desktop system and, more particularly, to an in-memory virtual desktop system, which stores and operates a virtual desktop image in main memory.
2. Description of the Related Art
A virtual desktop system is technology for executing a plurality of virtual machines on a single physical server using virtualization technology and allowing clients, connected to the physical server over a network, to use the virtual machines. For this, a hypervisor generates logical resources from the physical resources of the server using virtualization technology and provides the logical resources to the virtual desktops. Representative physical resources include a Central Processing Unit (CPU), memory, and a disk. The virtual desktops are operated on logical resources and are transferred to a client through a virtual desktop transmission module.
A hypervisor generates a virtual disk from a physical disk using virtualization technology, and provides the virtual disk to a virtual desktop. The virtual desktop provides a service using the received virtual disk.
An environment in which an operating system (OS) and an application program for a virtual desktop are installed in a virtual disk is called a virtual desktop image. To boot and operate a virtual desktop, the virtual desktop image must always be accessed.
FIG. 1 illustrates a conventional system for storing and operating a virtual desktop image on a hard disk. In FIG. 1, a hypervisor 12 generates a virtual CPU 14a, virtual main memory 14b, and a virtual disk 14c based on a physical CPU 10a, main memory 10b, and a disk 10c, and provides the generated resources to each virtual desktop 14. The virtual desktop 14 is operated based on the virtual CPU 14a, the virtual memory 14b, and the virtual disk 14c. 
The virtual desktop transmission module of the hypervisor 12 transmits the virtual desktop 14 to a client 16 over a network.
In a single virtual desktop server, several tens of virtual desktops 14 are operated. When all of the virtual desktops 14 simultaneously access the virtual desktop image, as in the case of virtual desktop booting, the load is concentrated on the disk 10c on which the virtual desktop image is stored, and thus a problem arises in that the performance of the entire system is deteriorated. In particular, the speed of the disk 10c becomes remarkably lower than that of other resources (CPU or memory) in the virtual desktop server, and thus the deterioration of system performance becomes even more serious.
As preceding technologies related to the present invention, U.S. Patent Application Publication Nos. 2014-0013045 (entitled “Non-Volatile RAM Disk”), 2014-0173171 (entitled “System and Method to Create a Non-Volatile Bootable RAM Disk”), and 2011-0131390 (entitled “Deduplication of Data on Disk Devices using Low-Latency Random Read Memory”) are disclosed.